﻿using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Runtime.InteropServices;

namespace RainmeterCustomized
{
    public static class IconTool
    {
        public static Boolean Large = true;
        public static Boolean Small = false;

        /// <summary>

        /// Used to access system folder icons.

        /// </summary>

        /// <param name="largeIcon">Specify large or small icons.</param>

        /// <param name="openFolder">Specify open or closed FolderType.</param>

        /// <returns>The requested Icon.</returns>

        public static Icon GetIconForFolder(Boolean largeIcon, Boolean openFolder)
        {
            SHFILEINFO _SHFILEINFO = new SHFILEINFO();

            try
            {
                IntPtr _IconIntPtr = SHGetFileInfo(@"", 0, ref _SHFILEINFO, (uint)Marshal.SizeOf(_SHFILEINFO), (uint)(SHGFI_ICON | SHGFI_LARGEICON));
                if (_IconIntPtr.Equals(IntPtr.Zero)) return null;
                Icon _Icon = System.Drawing.Icon.FromHandle(_SHFILEINFO.hIcon);
                return (Icon)_Icon.Clone();
            }
            finally
            {
                DestroyIcon(_SHFILEINFO.hIcon);        // Cleanup
            }
        }



        /// <summary>

        /// Used to access file icons for a given extension.

        /// </summary>

        /// <param name="extension">The file extension to get the icon for.</param>

        /// <param name="largeIcon">Specify large or small icons.</param>

        /// <param name="linkOverlay">Specify link overlay on the icon.</param>

        /// <returns>The requested Icon</returns>

        public static Icon GetIconForFileExtension(String extension, Boolean largeIcon, Boolean linkOverlay)
        {

            if (!extension.StartsWith("."))

                extension = "." + extension;



            SHFILEINFO shellFileInfo = new SHFILEINFO();

            try
            {

                uint flags = SHGFI_ICON | SHGFI_USEFILEATTRIBUTES;

                flags |= linkOverlay ? SHGFI_LINKOVERLAY : 0;

                flags |= largeIcon ? SHGFI_LARGEICON : SHGFI_SMALLICON;



                SHGetFileInfo(extension,

                    FILE_ATTRIBUTE_NORMAL,

                    ref shellFileInfo,

                    (uint)Marshal.SizeOf(shellFileInfo),

                    flags);



                return (Icon)Icon.FromHandle(shellFileInfo.hIcon).Clone();

            }

            finally
            {

                DestroyIcon(shellFileInfo.hIcon);

            }

        }



        #region P/Invoke

        private const int MAX_PATH = 256;



        private const uint SHGFI_ICON = 0x000000100;

        private const uint SHGFI_LINKOVERLAY = 0x000008000;

        private const uint SHGFI_LARGEICON = 0x000000000;

        private const uint SHGFI_SMALLICON = 0x000000001;

        private const uint SHGFI_OPENICON = 0x000000002;

        private const uint SHGFI_USEFILEATTRIBUTES = 0x000000010;



        private const uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;

        private const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;



        [StructLayout(LayoutKind.Sequential)]

        private struct SHFILEINFO
        {

            public const int NAMESIZE = 80;

            public IntPtr hIcon;

            public int iIcon;

            public uint dwAttributes;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]

            public string szDisplayName;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = NAMESIZE)]

            public string szTypeName;

        };



        [DllImport("Shell32.dll")]

        private static extern IntPtr SHGetFileInfo(

            string pszPath,

            uint dwFileAttributes,

            ref SHFILEINFO psfi,

            uint cbFileInfo,

            uint uFlags

            );



        [DllImport("User32.dll")]

        private static extern int DestroyIcon(IntPtr hIcon);

        #endregion

    }

}

